<?php
/**
 * Akeeba Engine
 * The modular PHP5 site backup engine
 * @copyright Copyright (c)2009-2012 Nicholas K. Dionysopoulos
 * @license GNU GPL version 3 or, at your option, any later version
 * @package akeebaengine
 *
 */

// Protection against direct access
defined('AKEEBAENGINE') or die('Restricted access');

/**
 * Akeeba filtering feature
 */
final class AECoreFilters extends AEAbstractObject
{
	/** @var array An array holding data for all defined filters */
	private $filter_registry = array();

	/** @var array Hash array with instances of all filters as $filter_name => filter_object */
	private $filters = array();

	/** @var bool True after the filter clean up has run */
	private $cleanup_has_run = false;

	/**
	 * Public constructor, loads filter data and filter classes
	 */
	public final function __construct()
	{
		static $initializing = false;

		parent::__construct(); // Call parent's constructor

		// Load filter data from platform's database
		AEUtilLogger::WriteLog(_AE_LOG_DEBUG,'Fetching filter data from database');
		$this->filter_registry = AEPlatform::getInstance()->load_filters();

		// Load platform, plugin and core filters
		$this->filters = array();
		$locations = array(
			AEFactory::getAkeebaRoot().DIRECTORY_SEPARATOR.'plugins'.DIRECTORY_SEPARATOR.'filters',
			AEFactory::getAkeebaRoot().DIRECTORY_SEPARATOR.'filters'
		);
		$platform_paths = AEPlatform::getInstance()->getPlatformDirectories();
		foreach($platform_paths as $p) {
			$locations[] = $p.'/filters';
		}
		AEUtilLogger::WriteLog(_AE_LOG_DEBUG,'Loading filters');
		foreach($locations as $folder)
		{
			$is_platform = $this->isPlatformDirectory($folder);
			$files = AEUtilScanner::getFiles($folder);
			if($files === false) continue; // Skip inexistent folders
			if(empty($files)) continue; // Skip no-match folders

			// Loop all files
			foreach($files as $file)
			{
				if( substr($file,-4) != '.php' ) {
					continue; // Skip non-PHP files
				}
				if( in_array(substr($file,0,1), array('.','_'))) {
					continue; // Skip filter files starting with dot or dash
				}
				$filter_name = ($is_platform ? 'Platform' : '').ucfirst(basename($file,'.php')); // Extract filter base name
				if(array_key_exists($filter_name, $this->filters)) {
					continue; // Skip already loaded filters
				}
				AEUtilLogger::WriteLog(_AE_LOG_DEBUG,'-- Loading filter '.$filter_name);
				$this->filters[$filter_name] = AEFactory::getFilterObject($filter_name); // Add the filter
			}
		}
		
		// Load platform, plugin and core stacked filters
		$locations = array(
			AEFactory::getAkeebaRoot().DIRECTORY_SEPARATOR.'plugins'.DIRECTORY_SEPARATOR.'filters'.DIRECTORY_SEPARATOR.'stack',
			AEFactory::getAkeebaRoot().DIRECTORY_SEPARATOR.'filters'.DIRECTORY_SEPARATOR.'stack'
		);
		$platform_paths = AEPlatform::getInstance()->getPlatformDirectories();
		$platform_stack_paths = array();
		foreach($platform_paths as $p) {
			$locations[] = $p.'/filters';
			$locations[] = $p.'/filters/stack';
			$platform_stack_paths[] = $p.'/filters/stack';
		}
		
		$config = AEFactory::getConfiguration();
		AEUtilLogger::WriteLog(_AE_LOG_DEBUG,'Loading optional filters');
		foreach($locations as $folder)
		{
			$is_platform = $this->isPlatformDirectory($folder);
			$files = AEUtilScanner::getFiles($folder);
			if($files === false) continue; // Skip inexistent folders
			if(empty($files)) continue; // Skip no-match folders

			// Loop all files
			foreach($files as $file)
			{
				if( substr($file,-4) != '.php' ) continue; // Skip non-PHP files
				$bare_name = strtolower(basename($file,'.php'));
				$filter_name = 'Stack'.($is_platform ? 'Platform' : '').ucfirst(basename($file,'.php')); // Extract filter base name
				if(array_key_exists($filter_name, $this->filters)) continue; // Skip already loaded filters
				if( !file_exists( $folder.'/'.substr($file,0,-4).'.ini' ) ) continue; // Make sure the INI file also exists
				$key = "core.filters.$bare_name.enabled";
				if($config->get($key,0)) {
					AEUtilLogger::WriteLog(_AE_LOG_DEBUG,'-- Loading optional filter '.$filter_name);
					$this->filters[$filter_name] = AEFactory::getFilterObject($filter_name); // Add the filter
				}
			}
		}
	}
	
	private function isPlatformDirectory($path)
	{
		static $allPlatformPaths = array();
		
		if(empty($allPlatformPaths)) {
			$platform_paths = AEPlatform::getInstance()->getPlatformDirectories();
			foreach($platform_paths as $p) {
				$allPlatformPaths[] = AEUtilFilesystem::TranslateWinPath($p.'/filters');
				$allPlatformPaths[] = AEUtilFilesystem::TranslateWinPath($p.'/filters/stack');
			}
		}
		
		$search = AEUtilFilesystem::TranslateWinPath($path);
		return in_array($search, $allPlatformPaths);
	}

	/**
	 * Extended filtering information of a given object. Applies only to exclusion filters.
	 * @param	string	$test		The string to check for filter status (e.g. filename, dir name, table name, etc)
	 * @param	string	$root		The exclusion root test belongs to
	 * @param	string	$object		What type of object is it? dir|file|dbobject
	 * @param	string	$subtype	Filter subtype (all|content|children)
	 * @param 	string	$by_filter	[out] The filter name which first matched $test, or an empty string
	 * @return	bool	True if it is a filtered element
	 */
	public final function isFilteredExtended($test, $root, $object, $subtype, &$by_filter)
	{
		if(!$this->cleanup_has_run)
		{
			// Loop the filters and clean up those with no data
			foreach($this->filters as $filter_name => $filter)
			{
				if(!$this->filters[$filter_name]->hasFilters()) unset($this->filters[$filter_name]); // Remove empty filters
			}
			$this->cleanup_has_run = true;
		}

		$by_filter = '';
		if(!empty($this->filters))
		{
			foreach($this->filters as $filter_name => $filter)
			{
				if($filter->isFiltered($test, $root, $object, $subtype))
				{
					$by_filter = strtolower($filter_name);
					return true;
				}
			}

			// If we are still here, no filter matched
			return false;
		}
		else
		{
			return false;
		}
	}

	/**
	 * Returns the filtering status of a given object
	 * @param	string	$test		The string to check for filter status (e.g. filename, dir name, table name, etc)
	 * @param	string	$root		The exclusion root test belongs to
	 * @param	string	$object		What type of object is it? dir|file|dbobject
	 * @param	string	$subtype	Filter subtype (all|content|children)
	 * @return	bool	True if it is a filtered element
	 */
	public final function isFiltered($test, $root, $object, $subtype)
	{
		$by_filter = '';
		return $this->isFilteredExtended($test, $root, $object, $subtype, $by_filter);
	}

	/**
	 * Returns the inclusion filters for a specific object type
	 * @param	string	$object	The inclusion object (dir|db)
	 * @return unknown_type
	 */
	public final function &getInclusions($object)
	{
		$inclusions = array();
		if(!empty($this->filters))
		{
			foreach($this->filters as $filter_name => $filter)
			{
				$new_inclusions = $filter->getInclusions($object);
				if(!empty($new_inclusions))
				{
					$inclusions = array_merge($inclusions, $new_inclusions);
				}
			}
		}

		return $inclusions;
	}

	/**
	 * Returns the filter registry information for a specified filter class
	 * @param	string	$filter_name	The name of the filter we want data for
	 * @return	array	The filter data for the requested filter
	 */
	public final function &getFilterData($filter_name)
	{
		if( array_key_exists($filter_name, $this->filter_registry) )
		{
			return $this->filter_registry[$filter_name];
		}
		else
		{
			$dummy = array();
			return $dummy;
		}
	}

	/**
	 * Replaces the filter data of a specific filter with the new data
	 * @param	string	$filter_name	The filter for which to modify the stored data
	 * @param	string	$data			The new data
	 */
	public final function setFilterData($filter_name, &$data)
	{
		$this->filter_registry[$filter_name] = $data;
	}

	/**
	 * Saves all filters to the platform defined database
	 * @return bool	True on success
	 */
	public final function save()
	{
		return AEPlatform::getInstance()->save_filters($this->filter_registry);
	}

	/**
	 * Get SQL statements to append to the database backup file
	 * @param string $root
	 * @return string
	 */
	public final function &getExtraSQL($root)
	{
		$ret = "";
		if( count($this->filters) >= 1 )
		{
			foreach($this->filters as $filter_name => $filter)
			{
				$extra_sql = $filter->getExtraSQL($root);
				if( !empty($extra_sql) )
				{
					if(!empty($ret)) $ret .= "\n";
					$ret .= $extra_sql;
				}
			}
		}
		return $ret;
	}
	
	/**
	 * Checks if there is an active filter for the object/subtype requested.
	 * 
	 * @param string $object The filtering object: dir|file|dbobject|db
	 * @param string $subtype The filtering subtype: all|content|children|inclusion
	 * @return bool
	 */
	public final function hasFilterType($object, $subtype = null)
	{
		foreach($this->filters as $filter_name => $filter)
		{
			if($filter->object == $object) {
				if(is_null($subtype)) {
					return true;
				} elseif($filter->subtype == $subtype) {
					return true;
				}
			}
		}
		return false;
	}

}